Anti-backflow drainage system



United States Patent 3,478,882 ANTI-BACKFLOW DRAINAGE SYSTEM Arno Hiirnemann, In der Luft 27, Obrighoven, Wesel, Germany Filed Jan. 31, 1968, Ser. No. 701,978 Claims priority, application Germany, Jan. 31, 1967,

Int. 01. B0 1d 33/38 US. Cl. 210-104 10 Claims ABSTRACT OF THE DISCLOSURE My present invention relates to a drainage system having means for preventing backflow from a sewer, cesspool or other waste-disposal installation to which the system is permanently connected.

The use of floating valve members, especially balls, has already been proposed for the purpose of sealing a cellar drain or the like against water backing up from the sewage system; reference in this connection may be made to U.S. Patent No. 1,700,636. The ball in such case must be held sufiiciently firmly against the seat to form an odor trap, particularly if the drain is installed indoors, yet must yield to relatively low hydraulic pressure from without a facilitate the discharge of even minor accumulations of water. A check valve of this type is therefore quite sensitive to solid particles which may become wedged between its ball and its seat and which prevent full closure; moreover, when the valve is opened by the weight of water to be drained, a wave of backwash from the sewer may come to the surface before the ball again reaches its position of closure.

The principal object of my invention is to provide an installation of the general character described which effectively seals the drain at all times against odor and back-flow from the waste-disposal system without substantially impeding the discharge of accumulating water.

A more specific object of this invention is to provide means in such installation for keeping sand and other solids from being entrained into the trap.

I e 0 r In accordance with the present invention, I provide a receptacle to be mounted in the usual manner at the lowest point of a floor to be drained, this receptacle having a preferably removable cover with an apertured portion overlying an overflow compartment of the receptacle; the overflow compartment advantageously contains a pail serving as a trap for sand and other solids that may be swept into the receptacle through the grillwork or other drain apertures in the cover. The overflow compartment communicates with an adjoining main chamber having an inlet near its top and an outlet at a lower level. A first floating valve member, preferably a ball, seals the inlet from within in the presence of appreciable water accumulation within the chamber, the outlet being normally sealed by a second valve member floating on a pool of water discharged into a recess of an adjoining drain pipe. When the water rises in the main chamber to a level suificient to repress the ball or other valve member in its outlet, the first valve member is concurrently raised to close the inlet; in this way, no continuous flow path ever exists between the drain and the disposal system so that any backwash past the second check valve will be stopped by the first check valve.

3,478,882 Patented Nov. 18, 1969 "ice The invention will be described with greater detail with reference to the accompanying drawing in which:

FIG. 1 is a top view (partly broken away) of a drainage system according to the invention;

FIG. 2 is a longitudinal sectional view taken on the line II-II of FIG. 1; and

FIG. 3 is a cross-sectional view taken substantially on the line IIII1I of FIG. 1.

The system shown in the drawing comprises a receptacle I normally closed by a cover 6 which is partly formed with a grillwork for the passage of water to be drained from a floor 30 (FIG. 2). A vertical partition 19 subdivides the interior of receptacle 1 into an overflow compartment 2 and a main chamber 3, the latter being formed by a vessel 8 resting with an upper flange 8' on partition 19; this partition has a multiplicity of frustoconical perforations diverging toward vessel 8. The vessel has external flanges 21 by which it is secured, with the aid of screws 23, to an end wall 22 of receptacle 1, this wall being open toward and rigid with an adjoining discharge pipe 7 into which an extension 13 of vessel 8 projects. Pipe 7 is recessed at 7' to collect a pool of water 31 on which a ball 17 floats to obstruct an outlet 10 in the underside of extension 13, this outlet being bounded by an annular lip 14 of soft rubber or similar resilient material. One or more baflles 18 limit the mobility of ball 17 to the vicinity of outlet 10.

Another such ball 16 floats on an accumulation of water 32 inside main chamber 3 and, upon a rise in the water level, is guided by baffles 18 toward an inlet 11 which is bounded by an annular sealing lip 12 of soft rubber or the like. In contradistinction to ring 14, which forms a slightly inclined valve seat for ball 17, ring 12 is horizontally disposed above the level of extension 13. The open top of vessel 8 is overlain by a lid which is partly cut away at 25 to give access to the inlet mouth 12; this lid has a bulging central portion 26 forming a downwardly facing spherical concavity of substantially the same radius as ball 16 so as to accommodate the latter in its top position illustrated in dot-dash lines in FIG. 2.

Water overflowing the compartment 2 may pass through a gap 9 into the vessel 8 by way of the cutouts 25 of lid 25, the area of these cutouts being so restricted that the hydrostatic pressure of an expected water accumulation on floor 30 will be incapable of dislodging the ball 16 from its top position as long as the water in vessel 8 is prevented by a backup of liquid in pipe 7 from escaping through outlet 10.

A pail 4 is removably disposed in compartment 2 and serves as a trap for sand. and other solids dropped through the grate 5. The pail may be extracted from vessel 8 by a handle 4' upon removal of cover 6 which for this purpose is provided with a hinged eye 34. Pail 4 also has narrow slots 4" through which water can run out into compartment 2, the water then penetrating the perforations 20 and collecting in receptacle 1 around vessel 8 whose connection with the receptacle 1 is sealed by a packing ring 24 surrounding the extension 13.

In the operation of my improved drainage system, outlet 10 of chamber 3 is normally closed by the ball 17 floating on the pool 31. As long as the overflow from compartment 2 into vessel 8 does not create an accumulation 32 to a level high enough to dislodge the ball 17, chamber inlet 11 will be open. After a certain amount of water has been collected in vessel 8, ball 17 will come to rest against its seat 12 but will be readily displaceable therefrom by further overflow from compartment 2 until the liquid volume in vessel 8 is suflicient to open the outlet 10 and to drain the vessel to its minimum level. If a tide of backflow from pipe 7 should occur while the ball 17 is out of position, the inrushing water would immediately urge the ball 16 more firmly against the sealing ring 12 which deforms, as indicated in dot-dash lines in FIG. 2, as the ball 16 rises toward contact with lid 25; even upon such deformation, the inlet to chamber 3 remains fully sealed. Thus, even the instrusion of solid matter between ball 17 and seat 14 will not allow the backwash to reach the overflow compartment 2, let alone the apertures of grate 5. Such solid matter will be swept back into pipe 7 as soon as the tide therein recedes and the liquid filling the vessel 8 is discharged therefrom.

The illustrated position of outlet seat 14, in a plane inclined at a small angle to the horizontal, in combination with the inversely sloping baffles 18 insures that the ball 17 is positively guided toward its seat while floating on the shallow pool of water 31 in the generally horizontal pipe 7.

Thus, the drainage installation according to my inven tion acts at all times as an effective odor trap and antibackflow device without the need for any manually operable valves or shutters. At most indoor installations, the pail 4 will have to be emptied only at long intervals.

I claim:

1. An anti-backflow drainage system, comprising a receptacle for drain water; partition means dividing the interior of said receptacle into a main chamber and an adjoining overflow compartment open at the top, said vessel being provided with a cover which is apertured above said compartment for admitting drain water into same; inlet means forming a mouth near the top of said chamber for receiving water overflowing said compartment; a first valve member floatable in said chamber on water accumulated therein for sealing said mouth upon the accumulated water reaching a predetermined level; outlet means in said chamber forming a port substantially at said predetermined level for the discharge of water from said chamber; conduit means communicating with said port for receiving the discharged water, said conduit means having a recess to retain a pool of discharged water adjacent said port; and a second valve member fioatable on said pool for normally sealing said port from without.

2. A system as defined in claim 1 wherein said conduit means comprises a generally horizontal pipe rigid with said receptacle, said chamber comprising a vessel seated in said receptacle and formed with an extension projecting into said pipe, said outlet means being disposed on said extension.

3. A system as defined in claim 2 wherein said partition means comprises a perforated wall adjacent said vessel.

4. A system as defined in claim 3 wherein the perforations of said wall diverge toward said vessel.

5. A system as defined in claim 2 wherein said vessel is provided with external flanges, further comprising fastening means securing said vessel to said receptacle by said flanges.

6. A system as defined in claim 2 wherein said vessel is provided with a lid partly obstructing said mouth.

7. A system as defined in claim 6 wherein said first valve member is a ball, said lid having a downwardly facing spherical concavity accommodating said ball in a raised position thereof, said inlet means including a flexible annular gasket allowing said ball to rise into contact with said concavity.

8. A system as defined in claim 7 wherein said lid is partly cut away at said concavity for exposing a fragmentaiy area of said ball in an elevated position thereof.

9. A system as defined in claim 2 wherein said extension has a sloping undersurface overhanging said pool, said outlet means being disposed at said undersurface.

10. A system as defined in claim 1, further comprising a pail disposed in said compartment underneath the aper- Itured part of said cover and withdrawable from said vessel upon removal of said cover.

References Cited UNITED STATES PATENTS 486,177 11/1892 Couzcns 210l63 X 2,504,474 4/1950 Oss 210-121 2,796,988 6/1957 Lofiler 210163 X 2,868,380 1/1959 Vecchio 210104 X REUBEN FRIEDMAN, Primary Examiner J. W. ADEE, Assistant Examiner US. Cl. X.R. 2l01l9 

